Re: 3-word compound adjectives; the return of the '-'

[Dave Kemper]

On 10/12/22, G. Branden Robinson <g.branden.robinson@gmail.com> wrote:
> Similarly, we say "thirty year-old bug"

The singular might be unambiguous that way, but the hyphen
disambiguates the plural: "thirty year-old bugs" is 30 bugs that are a
year old, whereas "thirty-year-old bugs" is an unspecified number of
bugs that are 30 years old.  Given that, omitting the first hyphen in
the singular case looks odd: for consistency it ought to be applied
there too, since you're clearly not talking about "30 bug."

Plus, that hyphen is conventionally used even in noun form: "Stop
acting like a thirty-year-old."